Tyre choice is really personal, Avon are a well known and respected brand, Bentley use them so cant be all bad!
There seems to be 3 tiers of tyre companies -
lowest are the chinese copy tyres ie your linglongs and wanlis, i would say avoid as they are cheap for a reason, i think Autocar did a test where the stopping distance in the wet was quite a few car lengths more than a branded tyre!
Middle are your Nexen / Kuhmo / Falken tyres, i think are ok if on a really tight budget, some people swear by them, others less so.
Top are your main brands, Goodyear, Continental, Avon, Michelin, Dunlop etc, companies that spend a lot on R&D.
I went with Avons from Mytyre as they were £82 each fitted where every other tyre site had them over £110! I had some Goodyear F1s from them in the summer and they were cheapest then too, im not going back to those tyres as they only lasted 10k miles and i dont need super grippy tyres for my (fairly) sedate driving style!